WowAce

What steps will reproduce the problem?
All I did was click the minimap button to sort my inventory.

What is the expected output? What do you see instead?
Looks like everything sorted ok, but I got an error message.

What version of the product are you using?
10.2.11b

Do you have an error log of what happened?

Date: 2013-07-07 17:31:03
ID: 1
Error occured in: Global
Count: 1
Message: attempt to compare two nil values
Debug:
   [C]: sort()
   MrPlow\PlowEngine.lua:822: ?()
   MrPlow\PlowEngine.lua:915:
      MrPlow\PlowEngine.lua:899
Locals:
(*temporary) = <table> {
7 = <table> {
}
9 = <table> {
}
}
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil

AddOns:
  Swatter, v4.3.1 (<%codename%>)
  AckisRecipeList, v2.4.8
  ACP, v3.4.3
  Altoholic, v5.3.001
  AntiPetBattle, v1.0.3
  Atlas, v1.25.00
  AtlasBurningCrusade, v1.25.00
  AtlasCataclysm, v1.25.00
  AtlasClassicWoW, v1.25.00
  AtlasDungeonLocs, v1.25.00
  AtlasScenarios, v1.25.01
  AtlasTransportation, v1.25.01
  AtlasWrathoftheLichKing, v1.25.00
  AtlasLootLoader, vv7.06.00
  AtlasMajorCitiesEnhanced, vv1.01
  AucAdvanced, v5.17.5413 (NeedyNoddy)
  AucFilterBasic, v5.17.5413 (NeedyNoddy)
  AucFilterOutlier, v5.17.5413.5347(5.17/embedded)
  AucMatchUndercut, v5.17.5413.5364(5.17/embedded)
  AucScanData, v5.17.5413 (NeedyNoddy)
  AucStatHistogram, v5.17.5413 (NeedyNoddy)
  AucStatiLevel, v5.17.5413 (NeedyNoddy)
  AucStatPurchased, v5.17.5413 (NeedyNoddy)
  AucStatSales, v5.17.5413.5376(5.17/embedded)
  AucStatSimple, v5.17.5413 (NeedyNoddy)
  AucStatStdDev, v5.17.5413 (NeedyNoddy)
  AucStatWOWEcon, v5.17.5413.5323(5.17/embedded)
  AucUtilAHWindowControl, v5.17.5413.5347(5.17/embedded)
  AucUtilAppraiser, v5.17.5413.5393(5.17/embedded)
  AucUtilAskPrice, v5.17.5413.5347(5.17/embedded)
  AucUtilAutoMagic, v5.17.5413.5392(5.17/embedded)
  AucUtilCompactUI, v5.17.5413.5400(5.17/embedded)
  AucUtilEasyBuyout, v5.17.5413.5347(5.17/embedded)
  AucUtilFixAH, v5.17.5413 (NeedyNoddy)
  AucUtilItemSuggest, v5.17.5413.5365(5.17/embedded)
  AucUtilPriceLevel, v5.17.5413.5365(5.17/embedded)
  AucUtilScanButton, v5.17.5413.5403(5.17/embedded)
  AucUtilScanFinish, v5.17.5413.5347(5.17/embedded)
  AucUtilScanProgress, v5.17.5413.4979(5.17/embedded)
  AucUtilScanStart, v5.17.5413.5347(5.17/embedded)
  AucUtilSearchUI, v5.17.5413.5373(5.17/embedded)
  AucUtilSimpleAuction, v5.17.5413.5388(5.17/embedded)
  AucUtilVendMarkup, v5.17.5413.4828(5.17/embedded)
  AutoRepair, v
  Babylonian, v5.1.DEV.332(/embedded)
  Bagnon, v5.3.4
  BagnonConfig, v
  BeanCounter, v5.17.5413 (NeedyNoddy)
  BOPCraftConfirm, v1.1.0
  CollectMe, v2.4.2
  Configator, v5.1.DEV.344(/embedded)
  DataStore, v5.3.001
  DataStoreAchievements, v5.3.001
  DataStoreAgenda, v5.3.001
  DataStoreAuctions, v5.3.001
  DataStoreCharacters, v5.3.001
  DataStoreContainers, v5.3.001
  DataStoreCrafts, v5.3.001
  DataStoreCurrencies, v5.3.001
  DataStoreInventory, v5.3.001
  DataStoreMails, v5.3.001
  DataStorePets, v5.3.001
  DataStoreQuests, v5.3.001
  DataStoreReputations, v5.3.001
  DataStoreSpells, v5.3.001
  DataStoreStats, v5.3.001
  DataStoreTalents, v5.3.001
  DBMCore, v
  DBMLDB, v
  DebugLib, v5.1.DEV.337(/embedded)
  Enchantrix, v5.17.5413 (NeedyNoddy)
  EnchantrixBarker, v5.17.5413 (NeedyNoddy)
  Gatherer, v4.3.1
  GoingPriceUS, v5.3.1373155200
  GoingPriceUSDemonSoul, v5.3.1372474015
  GTFO, v4.23.5
  LibExtraTip, v5.12.DEV.350(/embedded)
  Mapster, v1.5.4
  MrPlow, v10.2.11
  Outfitter, v5.9.1
  Postal, v3.5.1
  ReforgeLite, v1.32
  SlideBar, v4.3.1 (<%codename%>)
  Stubby, v5.17.5413 (NeedyNoddy)
  TipHelper, v5.12.DEV.351(/embedded)
  Titan, v5.1.21.50300
  TitanBag, v5.1.21.50300
  TitanClock, v5.1.21.50300
  TitanGold, v5.1.21.50300
  TitanLocation, v5.1.21.50300
  TitanLootType, v5.1.21.50300
  TitanPerformance, v5.1.21.50300
  TitanRepair, v5.1.21.50300
  TitanSpec, v2.3.1
  TitanVolume, v5.1.21.50300
  TitanXP, v5.1.21.50300
  TomTom, vv50300-1.0.1
  BlizRuntimeLib_enUS v5.3.0.50300 <us>
  (ck=ce7)

If MrPlow is looping endlessly over a few items follow the instructions below:

1. Take note of which items are being swapped. Be aware, that it will almost always involve at least 3 items at most times.
2. use  /mp add [Blocky Item of Block][Womble cabbage of Frog][Fried Green Tomatoes] (use shift-click on the items)
3. run /mp sort and copy/paste the resultant output to the ticket (after hitting /mp stop after it loops)
4. note /mp watching and /mp clear will show what's being monitored and clear the list respectively.

Please provide any additional information below.